Awesome!
But why one category for both 3v3 and 4v4? Because if you make a (4-6) map you're kina screwed then aren't you?
No, you won't be screwed. Your map doesn't need to be playable by 8 players to win that category. It will be judged for what it is.
We combined those sizes in order to try to even out the submissions that we expect to get per category.